It means putting the flow of the "river of
grass" -as much as still possible- the way it was. Leaving the
flow unimpeded from lake Okeechobee to the Everglades, hopefully giving life again
to the coral reefs south of the Everglades National Park.

Why to buy?
Just for coral reefs instead of sugar
cane?

It is a lot more important than that!
Mostly since the 1930's the land around the lake -and all the way from
Orlando- was sold to farmers and cattle ranchers. Normally that is not
much of a
problem, it has been done all over the USA. The problem is that
fertilizer
run-off from those farms carry large amounts of phosphorous, an element
that promotes fast growth of algae bloom. Furthermore, Lake
Okeechobee levies were built to withstand a Category 3 hurricane after a
hurricane -in 1928- killed about 2000 people when it overflowed. This
barrier around the lake impedes the regular flow of water to the Everglades, the
US Army Corps of Engineers did not foresee any problem by withholding that water
and drying up the Everglades. When the lake is overloaded they just release the water into two channels reaching the
Atlantic Ocean in the east,
and the Gulf of Mexico in the west.

In other words, one channel discharges into the
St. Lucie River, and this river takes the water to the Indian River Lagoon,
causing great damage to its estuaries, as decades of pictures from LANDSAT
corroborate.
The other channel takes its flow to the Caloosahatchee river, which floods the
estuary in Tampa Bay, making a big ecological mess over there as well.

This cyclical flows are not natural, and cause
not only the algae blooms that take the light and oxygen from the water and
asphyxiate the sea-grass (which feeds a lot of creatures, including crabs,
shrimp, and manatees).
The other effect is to lower the salinity of the water. Many creatures
(whose niche is adaption to the estuaries habitat) die when salinity gets to high or too low.
Typically, 2% salinity is too low for most species in the estuaries.